Shock-absorber.



W. B.'KNAPP. SHOCK ABSORBER. APPLICATION FILED JUNE 10, 1909.

$49,654., Patented Feb. 15, 1910.

IIIIII M X WILLIAM BRUCE KNAPP, 0F STONEHAM, MASSACHUSETTS.

SHOCK-ABSORBER.

To all whom it may concern:

Be it known that 1, WILLIAM BRUCE KNArr, of Stoneham, county of Middlesex, State of Massachusett's, have invented an Improvement in Shock-Absorbers, of which the following isa specification.

This invention relates to shock-absorbers for automobiles and the like, of the type comprising a cylinder and'piston, connected one with the axle and the other with the frame of the vehicle, and having means for establishing open communication between the opposite end-portions of the cylinder, permitting movements of the piston and cylinder toward and from each other, and said piston bearing. check-valves permitting unrestrained movements of the piston and cylinder in a direction toward each other.

The invention has for its object to provide means whereby movements of the piston and cylinder in a direction toward each other are severely restrained during the last part of a long stroke yet unrestrained during the first part of such stroke, as Well as during short strokes.

Figure 1 is a longitudinal vertical section of a shock-absorber, embodying this invention. Fig. 2 is a plan View of the closingplate which is arranged in the cylinder and adapted to be engaged by the downwardly moving piston. Fig. 3 is a modified form of closin plate.

As here shown, a represents a hollow cylinder having closed ends or heads a, a and adapted to be filled with a non-congealable oil or equivalent material, and 6 represents a piston contained in said cylinder and attached to a piston-rod b, which extends through a suitable stufiing-box 6 The cylinder a, as here shown, has a by-pass 0, extending along its side from end to end or thereabout, for establishing open communication between the opposite end portions thereof, at opposite sides of the piston. The

piston 12, has one or more holes 6 through it, and valves 6 are provided for said holes, which may be of any suitable construction, adapted to operate as check-valves, opening when the piston is moving in one direction and closing when the piston is moving iii the opposite direction. Said cylinder and piston are adapted to be connected respec tively with the axle and frame of the vehicle by any suitable means. It is herein designed to close the hole or holes I) in the piston whensaid piston has moved in a di Specification of Letters Patent. Application filed June 10, 1909. Serial No. 561,317.

rection toward the cylinder for a suitable distance, so that further movement of the piston in the same direction will be severely restrained, although not checked. To, accomplish this result a closing-plate g is employed, which is made as a flat ring of suitable diameter to be contained in the cylinder, and said plate is arranged beneath the piston and in the downward path of moveinent thereof, so as to be engaged by it. Said Patented Feb. 15, 1910.

so. i

plate is particularly constructed to close the holes 6 when engaged by the piston, yet as a modified form of my invention said plate may have small holes through it, see Fig. 3, so that instead of wholly closing said holes itwill partially close them. Hence the closing-plate herein referred to may act either to wholly or partially close said holes. Said plate is secured to or has a collar g arranged at the center thereof, which is free 'to slide on a supporting and guiding-rod 9 arranged vertically in the cyllnder, and said plate is held yieldingly in a predetermined position by means of a lifting-spring 9 which encircles said rod g and bears at one end against the lower end of the cylinder and at the opposite end against the plate or collar thereof. The rod 9 as here shown,

has adjustably connected with it a limitingstop for limiting the upward movement of the closing-plate, and said stop consists of two collars g arranged on the screwthreaded end 0 said rod 9 The pistonrod is made tubular fora suitable portion of its length to receive said collars g 9 The spring 9 acts to lift the'closing-plate and hold it with its collar g in engagement with the end of the lowermost collar g. Said limiting-stop may be adjusted by turning the collars on the SL rew-threaded end portion of the rod g As the piston and cylinder move in a direction toward each other their movements will be unrestrained by the opening of the valves, until the piston engages the closln plate, and its further movement is severe y restrained by said plate'closing the hole or holes 12 although such further movement 1s not checked for the reason that/the by-pass a is in open communication with the cy-llnder at both ends. Hence during short movements of the piston and cylinder toward each other they are unrestrained, but during a long movement the first part thereofis unrestrained and the last, part severely rein a direction away from each other their ters Patent is 1. A shock-absorber comprising a cylinder and a piston contained therein having holes through it and having valves, and a movable closing-plate arranged in said cylinder, in the downward path of movement of the piston, for closing one or more of the holes therein, whereby further downward movement of the piston is restrained, substantially as described.

2. A shock-absorber comprising a cylinder and a piston contained therein having holes through it and having valves, and a'yieldingly supported closing-plate arranged in said cylinder, in the downward path of movement of the piston, for closing one or more of'the holes therein, whereby further downward movement of the piston is restrained, substantially as described.

3. A shock-absorber comprising a cylinder and a piston contained therein having holes through it and having valves, and a sliding closing-plate arranged in said cylinder, in the downward path of movement of the ist-on, for. closing one or more of the holes therein, whereby further downward movement of the piston is restrained, substantially as described.

4. A shock-absorber comprising a cylinder and a piston contained therein having holes through it and having valves, .and a movable closing-plate arranged in said cylinder, in the downward path of movement of the piston, for closing one or more of the holes therein, whereby. further downward movement of the piston is restrained, and an adjustable stop for limiting the upward movement of said closing-plate, substantially as described.

5. A shock-absorber comprising a cylinder and a piston contained therein having holes through it and having valves, and a movable closing-plate arranged in said cylinder, in the downward path of movement of the piston, for closing one or more of the holes therein, whereby further downward movement of the piston is restrained, and a guide-rod upon which said closing-plate sli es and a lifting-spring for said closingplate, substantially as described.-

6. A shock-absorber comprising a cylinder and a piston contained therein having holes through it and havingvalves, and a movable closing-plate arranged in said cylinder, in the downward path of movement of the piston, for closing one or more of the holes therein, whereby further downward movement of the piston is restrained, a guide-rod for said closing-plate having a screw-threaded end-portion and two collars arranged on said screw-threaded end-portion, which form an adjustable limiting-stop for the closing-plate, substantially as described.

7. In a shock-absorber, a cylinder having a longitudinal by-pass, a piston contained in said cylinder having valve-openings, valves for said openings, a movable closing-plate arranged in said cylinder, in the downward path of movement of the piston, adapted to be engaged and moved downward by said piston, and which, when in engagement with the piston, closes the valve-openings therein, whereby further downward movement of the piston is restrained, substantially as described.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

WILLIAM BRUCE KNAPP.

Witnesses:

B. J. Noms, H. B. DAVIS. 

